Paper: An Approach to Estimating Skin Damage and Appropriate Treatment Volumes

Nowhere in the oil field are experience and "rule of thumb" employed more frequently than in estimating chemical treatment volumes to be used to stimulate production. The majority of chemical treatments performed are attempts to improve fluid flow by removing restrictions around the wellbore. Usually, if the production rate has declined more rapidly than expected, it is an indication that a restriction exists or is forming. Darcy's equation for fluid flow through concentric cylinders empirically describes "skin damage". These theoretical curves relate productivity damage ratio to the extent and degree of damage. Combined with plots of treating radius vs. porosity, treatments can be evaluated. Also, general conclusions are possible from the shape of Darcy's theoretical curves. From these evaluations, a basis is available to estimate treatment volumes.